The alternative is fight a battle you have no chance of winning, all the while the area gets completely fucked up pretty much permanently.

There was opportunity for a peaceful resolution and they turned it down because they thought they could win, then the west (which had been egging them on up to that point) suddenly fucked off to do a genocide in the middle east leaving them high and dry.

At that point you would have no choice but to admit you fucked up and would have to accept worse peace terms. This isn’t a video game where winning is the only thing that matters; people’s lives are on the line. The longer you fight the more people that die, and for what?